Power semiconductor devices, such as power metal oxide semiconductor field effect transistors (MOSFETs), have been widely used in power switching devices, such as power supplies, rectifiers, low-voltage motor controllers, and so forth. Power semiconductor devices can be made with a trench topology to enhance power density.
Conventional fabrication processes for manufacturing a trench type power semiconductor device often involve several masks to accommodate forming complex structures, such as gate trenches and contact trenches. Using multiple masks to etch adjacent gate and contact trenches of different dimensions in different steps can be difficult and cause defects due to errors introduced by the mask dimensions and alignments thereof at each masking step. Variations in semiconductor device fabrication can also often lead to variations in device electrical performance such as on-state resistance (RDSon) and breakdown voltage.
Accordingly, there is a need to overcome the drawbacks and deficiencies in the art by substantially eliminating device defects in trench type power semiconductor devices while enhancing their electrical performance characteristics.